The subject of the present invention is a respiratory assistance apparatus that can be used on patients whose spontaneous respiration is absent or insufficient.
Respiratory assistance apparatuses are already known which make it possible for a respiratory gas coming from an external source to be taken into the lungs of a patient, said apparatuses comprising:
a chamber provided with a respiratory-gas inlet intended to be connected to said source and with a respiratory-gas outlet intended to be connected to an airway of said patient; and
an inflatable flexible bladder intended to bear on a part of said patient in order to seal between said respiratory-gas outlet and the outside.
Such known respiratory assistance apparatuses may, for example, take the form:
of a respiratory mask, said chamber of which is bounded by a hollow shell intended to be applied, by its opening which constitutes said gas outlet, to the face of the patient, enclosing the nose of the latter. The respiratory-gas inlet is then formed by an endpiece integral with the bottom of said shell, while said inflatable bladder has the shape of a bead going around the outline of the opening of said shell and interposed between said opening and the patient""s face; or else
of a nasal intubation device, said chamber of which is bounded by a tubular element intended to be inserted into a nostril of the patient. In this case, said respiratory-gas inlet and outlet are formed by the opposite ends of said tubular element and said inflatable bladder is in the form of a balloon carried by the external wall of said tubular element and interposed between the latter and the internal wall of the nostril.
Whatever the embodiments of these known respiratory assistance apparatuses, they have the drawback that their inflatable bladder cannot seal satisfactorily. This is because, in order to be able to withstand the inflation pressure, said flexible bladder must have a relatively thick wall which gives it a certain rigidity and consequently prevents it from exactly matching the irregularities in the relief of that part of said patient (the face or internal nostril wall, for example) to which it is applied. This therefore results in leakage, entailing expensive loss of respiratory gas. In addition, in the case of a mask, the respiratory gas passing between the bead and the patient""s face, as a result of the deficiencies in sealing by said bead, penetrates the patient""s eyes and is the cause of ocular irritations and of conjunctivitis.
In order to compensate for such sealing deficiencies, practitioners are forced:
to increase the pressure with which said inflatable flexible bladder is applied to the corresponding part of the patient. Such an increase in application pressure is obtained either by forcibly applying the mask to the face (using elastic straps passing behind the head for example) or by increasing the internal pressure of the balloon of the nasal intubation device. However, a high bladder application pressure results in the formation of sores at the places where the respiratory apparatus is applied to the patient; and/or
to increase the pressure to which the respiratory gas is taken into the respiratory apparatus. In this case, the mucous membranes reached by the respiratory gas may as a result be injured by this gas. In addition, in the latter case, gas leaks still occurxe2x80x94and are even exacerbatedxe2x80x94with their drawbacks.
The object o the invention is to remedy these drawbacks and relates to a respiratory assistance apparatus of the type indicated above, by virtue of which any risk of leakage of respiratory gas, at the inflatable bladder of said apparatus, may be avoided.
For this purpose, according to the invention, the respiratory assistance apparatus making it possible for a respiratory gas coming from an external source to be taken into the lungs of a patient, said apparatus comprising:
a chamber provided with a respiratory-gas inlet intended to be connected to said source and with a respiratory-gas outlet intended to be connected to an airway of said patient; and
a thin-wall inflatable flexible bladder intended to bear on a part of said patient in order to seal between said respiratory-gas outlet and the outside,
is noteworthy:
in that it includes an inflatable flexible envelope surrounding said inflatable flexible bladder; and
in that the wall thickness of said envelope is less than that of said inflatable bladder in order to give said envelope a greater flexibility than the flexibility of the latter.
Thus, when said inflatable flexible bladder cannot be sealingly applied against said bearing part of the patient, the space which results therefrom is closed off by said inflated flexible envelope, which thus ensures application sealing at the places where this sealing cannot be obtained by said inflatable bladder.
Preferably, said flexible envelope is made of a plastic film a few microns in thickness.
Said inflatable flexible envelope may be inflated in an appropriate manner either using a source of auxiliary pressure or using said external respiratory-gas source.
In one advantageous embodiment, said flexible envelope communicates, on one side of the bladder, with said chamber and, on the other side of said bladder, with the outside. Thus, said flexible envelope is therefore inflated by the pressurized respiratory gas coming from said chamber and being discharged to the outside.
If said respiratory assistance apparatus has the shape of a mask, said chamber of which is defined by a hollow shell intended to be applied, by its opening which constitutes said gas outlet, to the face of a patient, enclosing the latter""s nose, the respiratory-gas inlet being provided in the bottom of said shell and said inflatable bladder having the shape of a bead going around the perimeter of the opening of said shell and interposed between said opening and said face of the patient, it is advantageous for:
said flexible envelope to be a sleeve folded back around said bead, said sleeve having a part internal to said shell and a part external to said shell, these parts being connected to each other by an intermediate part bent back around said bead;
said internal part of the flexible envelope to define with the internal wall of said shell an internal space which, for example, communicates with said chamber; and
said external part of the flexible envelope to define with the external wall of said shell an external space which, for example, communicates with the outside.
Such a sleeve may either be removably attached to said shell or be integral with the latter. In the latter case, it is advantageous for said sleeve to be integral with the shell at the time of manufacture of the respiratory assistance mask, which may therefore be of the type which can be thrown away after use. On the other hand, in the first case, the sleeve may be attached at any moment to a respiratory mask originally manufactured without a sleeve.
In such a respiratory mask, said internal space may communicate with said chamber by virtue of at least one orifice provided through said internal wall of the sleeve. As regards said external space, this may either be open to the outside or may communicate with the outside by means of at least one orifice provided through said external part of the sleeve.
In the latter case, in order for said flexible envelope to be permanently inflated, it is preferable to ensure that the total flow section of the orifice or orifices provided through said internal part of the sleeve to be greater than the total flow section of the orifice or orifices provided through said external part of said sleeve.
In an alternative embodiment of the respiratory assistance apparatus according to the present invention, in which said apparatus includes a tubular element, the internal volume of which defines said chamber and which is intended to be inserted into a nostril of the patient, said respiratory-gas inlet and outlet being formed by the opposite ends of said tubular element and said inflatable bladder being in the form of an inner balloon supported by the external wall of said tubular element and interposed between the latter and the internal wall of said nostril, said flexible envelope may be in the form of an outer balloon surrounding said inner balloon and supported by said external wall of said tubular element.
Said outer balloon may then communicate, at its distal end, with said chamber via at least one orifice provided through the wall of said tubular element, and, at its proximal end, with the outside via at least one orifice provided through the wall of said outer balloon.
Here again, and for the same reason as mentioned above, the total flow section of the orifice or orifices provided through said wall of the tubular element is advantageously greater than the total flow section of the orifice or orifices provided through the wall of said outer balloon.